Deseaming apparatus



Dec. 19, 1944. w. J. JACOBSSON ,7 2,365,411

' DESEAMING APPARATUS I Filed July 24, 1940 INVENTOR WI I G OT J.JACOBSSON ATTORNEY Pdttthtdd h1g9, Haiti 2,365,411 nasaarvmvo arrane'rvsWiigot .r. .lacobsson, Plainfleld, n.

Unlonfiarhlde and C notation of New York 3., assignor to arbor:Corporation, a cor- Application July 24, 1940, @cflal No. 347,196

This invention relates to the art of thermochemically conditioning thesurfaces of ferrous metal bodies, such as ingots, billets, blooms,slabs,

and the like, and more particularly to apparatus for deseaming, in whicha stream of surface conditioning fluid, such as oxygen, is dischargedfrom a nozzle against a surface undergoing thermo chemical treatment.

Surface seams and other defects frequently appear in steel billets,blooms, slabs, etc., in the early stages of production; These aresometimes caused by imperiectionsin the surface of a steel body oringot, which imperfections are elongated in the first rolling and, asrolling is continued to produce a billet or bloom from the ingot,progress the length of the bloom or billet and form seams which alsoextend to an appreciable depth,

face deiectsfroin ferrous metal bodies, a surface area on the metal bodyto be conditioned is heated to the kindling temperature by anoxyacetylene preheating flame and then a stream of oxidizing gas, e. g.oxygen, is applied obliquely against the highly heated area. The greaterpart of the surface metal in the path. of the oxygen stre is oxidimd andthe remainder melted and blown away. Thus, as the inclined oxygen streamis advanced with respect to the surface of the body, successive surfaceportions are removed. The surface portions therebyremoved include thedefects or imperfections which would tend to cause seams duringlater'rolling operations, and the body is thus deseamed.

The efficiency of deseaming and surface conditionin operations isnormally measured by the relation between the amount or oxygen used andthe amount of metal removed. That is, approximately t? to 4.6 cubic feetof oxygen are theoretically required to oxidize one pound of steel, andwhen the amount of oxygen used is reduced, say to about 3 cubic feet ofoxygen per pound of steel removed, the efllciency is in creased.However, when the efilciency of the Jperation is increased so that lessoxygen is used;

ess metal lsoxidized and more metal is removed my melting. The reactionproducts which are ilown ahead of the advancing jet'of oxygen tend .opreheat subsequent surface portions to be re-.

s Claims. (or. lea-27.4)

blown'or flow to either side of the advancing jet solidify on thesurface at either side of the deseamed area", and produce what may betermed .fins." Since solidified ferrous oxides are friable" and ratherbrittle, fins composed principally of such oxides are easily removed,but fins having a greater proportion of solidified steel or ferrousmetal are more diflicult to remove. In some cases, such fins tenaciouslyadhere to the latvera] edges ofthe deseamed area, and may be bent backand forth several times before brealzing. In addition, it is alsodesirable to remove lateral slag accumulations and formations to vprovide the best condition for-subsequent rolling.

Among the objects of this invention are: to

provide a blowpipe for thermo chemically con-.

ditioning a surface of a ferrous metal body, in which a novel stream ofsurface conditioning fluid. such as oxygen, is produced and utilized toinhibit slag and fin production; to provide a nozzle inlet constructionfor controlling the fin and slag inhibiting characteristics of a streamof surface conditioning fluid or oxygen discharged from such nozzle; toprovidean im proved deseaming nozzle thatiis simple and economical inits parts, and very efilcient and ofnoveol, but the reaction productswhich are 56 fective in operation; to provide novel means for improvingthe slag and fin inhibiting characteristics of an oxidizing gas streamdischarged from a desearning nozzle; and to provide improvements'in theart of thermo-chemically conditioning the surfaces. of'ferrous metalbodies with a, single oxygen stream or a plurality of oxygen streams. I

Further objects and novel features of this invention will be apparentfrom the following description and accompanying drawing, in which:

Fig. 1 is a longitudinal sectional view of the head and nozzle of anoxy-acetylene blowpipe adapted to operate in accordance with theprinciples of this invention; and

Fig. 2 is an enlarged and of the nozzle of Fig. 1.

'In accordance with this invention, a stream ,of oxidizing gas oroxygen, a portion of which plan view of the. inner oxygen stream neednot be uniform. For example, in deseaming a steel body with a stream ofsubstantially pure oxygen, excellent results are obtained with a streamin which the velocity of the central portion of the stream varies over arange from 600 to 1000 feet per second and the velocity of the mosteffective peripheral portion charge passage it of a nozzle N, removablyse-.

cured to a head H of a conventional blowpipe. A stream of oxygen isdischarged from orifice ii of passage it, at the lower or outer end ofthe nozzle. Spud S is provided with a central passage i2 and a pluralityof outer passages i3, six in number as illustrated, although othernumbers of passages, even down to two, may be used. The passages i2 andi3 collectively constitute the nozzle inlet means for admitting theoxygen to. the passage I0. Passages l2 and iii are relatively small indiameter, are much shorter than passage i0,'and outer passages 53preferably symmetrically surround central passage l2. The passages .inspud S are each considerably longer than their respective diameters anddistribute the flow of oxygen through the nozzle in such a manner thatthe central portion of the stream discharged from orifice ll has ahigher velocity than the outer or peripheral portion of the stream; but,at the same time, the stream flows smoothly and without excessiveturbulence, which is a highly desirable characteristic, because themetal removal emciency of a non-turbulent stream is considerably greaterthan that of a turbulent stream.

In further accordance with this invention, as has been found byexperiment, the character istics of the stream may be altered bychanging the length or longitudinal position of the spud within thenozzle N. As an example of the latter, a spud ainch long used inconnection with the nozzle shown in the drawing, which is about fiveinches in length, the passage I being about 0.281 inch in diameter,produced the most satisfactory all-around results when the upstream endof the spud was flush with the inner end of the nozzle, in the positionshown in Fig. 1. When the spud per second and up to about 600 feet persecond. That any portion of the oxygen stream having a velocity above600 feet per second apparently tends to remove metal, whereas anyportion of the stream having a velocity somewhat below 600 feet persecond, and located at or near .the edge of the stream, apparently tendsmerely to remove slag and oxidme metal previously removed in moltenform. The most effective range for the latter, which apparently suppliesthe fin inhibiting and slag removal characteristics, was found to beabout 200 to soii'feet per second.

The nozzle N is a conventional. type, consisting of a generally tubularbody member of metal, such as swaged copper, which may be chromiumplated, but provided with a shoulder it on which spud S is seated. Inaddition to central oxygen passage it, which is rectilinear or straightand is substantially uniform in cross-section from endto-end, nozzle Nis provided with a plurality of equally spaced heating gas passages itsurrounding the central passage. Head H is also a part of a conventionaltype of blowpipe, and is provided with an oxygen passage i! and aheating gas passage it, to which tubes is and 20, respectively, conductoxygen and a combustible mixture of heating gases, such as a mixture ofoxygen and acetylene. Heating gas passage it connects with an annularspace 2i formed between head H and nozzle N, the annular space 2idistributing the heating gas to passages it in nozzle N. To providegas-tight seals between head H and nozzle N, and to prevent leakage ofoxygen or heating gas, the head and nozzle are provided with cooperatingconical seating surfaces 22 and 2t.

Nozzle N is secured to head H, and the conical seating surfaces 22 and223 are held in gas-tight engagement, bya nut 25 which engages threads26 in head H and which bears against an annular flange 21 formed onnozzle N. The inner or upper end of nozzle N extends into an annularspace 28, formed as a slight enlargement of oxygen passage ii, while theouter or lower end of the nozzie'is provided with a protective ring 28of relatively hard metal. Ring is may be formed of acobaltchromium-tungsten alloy of the type known as Stellite," and ispreferably cast separately, then secured to the nozzle in any suitablemanner, such as by welding, as shown. Head His also provided with a,protective shield 30, formed of the same or'similar metal as ring 29.Shield so may be cast onto head H, being locked securely thereto by akey 38 which is formed by metal flowing into was moved 3% inch, or adistance of its own length, into head H so that the opposite ordownstream end of the spud was flush with the inner end of the nozzle,the efiiciency of metal removal was increased, i. e. slightly lessoxygen was used to remove the same amount of steel, but the slag removaland fin inhibiting qualities were slightly decreased. Again, when thespud was moved toward the outer end of the nozzle so that the inner orupstream end of the spud was spaced inch, or its own length, from theinner end of the nozzle, the metal removal efficiency was slightlydecreased, but the slag removal and fin inhibiting qualities wereslightly improved. In

each of the above instances, the slag removal and fin inhibitingqualities were. of course, a considerable improvement over thosequalities in instances when the spud was not used.

In addition, it was also found by velocity measurements of the streamsdischarged from the nozzle during the above experiments, that a criticalrange apparently exists above 400 feet and solidifying in a suitablehole in head H, provided for the purpose. Ring Nanci shield 30 protectnozzle N and head H from excessive wear.

To thermo-chemically condition the surface of a ferrous metal body, thecombustible gas mixture supplied by tube 20 is turned on, and theheating flames ignited in the usual manner es they issue from passagesHS of-nozzle N. The

heating flames are applied to a relatively small erosion the surface ofthe body, and as soon as this area is heated to the ignitiontemperature, oxygen supplied through tube i9 is turned on. The streamdischarged through orifice ii of passage i0 is then applied to theheated area, thereby'removing a surface layer and forming a depression.The blowpipe is held with the nozzle at .a constant angle of about 30with respect to the surface and advanced relatively theretosubstantially in the direction of discharge of the oxygen stream, to cuta smooth groove having sloping sides in the surface of the metal body.

A series of closely spaced parallel grooves may be produced by two ormore deseaming nozzles operated side by side, and a layer from an entiresurface of a metal body may be removed by a sumcient number of nozzles.When two or more deseaming nozzles are thus used side by side, there isa tendency for a fin to form between each set of adjoining parallelgrooves, but with nozzles constructed in accordance with this invention,such fins are eliminated -or easily removed.

From the foregoing it will be apparent that this invention provides ablowpipe for thermochemically conditioning surfaces of ferrous metalbodies which is effective and can be constructed to produce a desiredrelation between the fin inhibiting qualities and the metal removingefficiency of a stream of deseaming Ox gen. It will also be apparentthat the apparatus necessary, over and above conventional parts, issimply and easily constructed, and very little change in a conventionaldeseaming nozzle is required to produce .a considerable improvement inthe fin inhibiting qualities of the oxygen stream discharged therefrom.

Although several changes have been described,

such as variations in the length and longitudinal position of spud S,and also variations in the number and/or size of the passages in spud S,it will be apparent to those skilled in the art that other changes andmodifications may be made without departing from this invention. It istherefore intended in the appended claims to cover all such changes andmodifications as fall within the true spirit and scope of thisinvention. a

What is claimed is:

1. A deseaming nozzle comprising, in combination, a generallytubularbody member having a central oxygen passage with a deliveryportion of substantially uniform cross-section from endto-end, and aplurality of heating gas passages surrounding said oxygen passage inspaced relation thereto; and'a spud disposed within said oxygen passageadjacent the inlet end of said delivery portion and having a pluralityof spaced symmetrically arranged passages each of considerably greaterlength than diameter, parallel to said oxygen passage and extendingthrough saidspud, for increasing the slag removal efllciency of theoxygen stream discharged by said oxygen passage. v

2. A deseaming nozzle having a centrally disposed longitudinal passageof cylindrical shape for discharging a stream of deseaming oxygen; andmeans associated passage for controlling the stream of deseaming oxygendischarged from the outlet end, of said passage and comprising an inserthaving a central passage concentric with the longitudinal axis ofsaidnozzle passage and a plurality of unirormly spaced passages surroundingsaid central passage.

3. A deseaming blowpipe nozzle for thermochemically removing metal fromthe surface of a ferrous metal body, said nozzle having a centrallongitudinal passage of cylindrical shape for discharging a stream ofoxidizing gas against the surface of said body; and means associatedwith the inlet portion of said passage for causing said stream ofoxidizing gas to have a central portion with the inlet end of said ofrelatively high velocity and an outer portion of relatively lowvelocity, said means comprising an insert having a central passageconcentric with the longitudinal axis of said nozzle passage and aplurality of uniformly spaced passages surrounding said central passage.

4. A blowpipe nozzle having preheating gas passages and an oxygenpassage extending longitudinally thereof, and also having a plurality ofinlet passages each considerably longer than its diameter but muchshorter and of smaller diameter than said oxygen passage, said inletpassages collectively constituting the nozzle inlet means for admittingoxygen to said oxygen passage.

5. A blowpipe for thermochemically removing metal from a metal bodycomprising nozzle means having preheating gas outlet passages and a maincylindrical passage for discharging a stream of oxidizing gas against asurface of said body; and a plurality of inlet passages collectivelyconstiuting the inlet means for supplying oxidizing gas to said mainpassage, said inlet 1 passages being each much shorter and of smallercross-sectional area than said main passage, and one of said inletpassages being coaxial with said main cylindrical passage.

6. A blowpipe for thermochemically removing metal from a metal bodycomprising nozzle means having preheating gas outlet passages and a maincylindrical passage for discharging a stream of oxidizing gas against asurface of said body;

body; and at least three inlet passages collectively constituting theinlet means for supplying oxidizing gas to said main passage, said inletpassages being each much shorter and of smaller cross-sectional areathan said main passage, and one of said inlet passages being coaxialwith said main cylindrical passage.

'7. A blowpipe for thermochemically removing metal from a metal bodycomprising nozzle means having preheating gas outlet passages and a maincylindrical passage for discharging a stream of oxidizing and-sevencylindrical inlet passages collectively constituting the inlet means forsupplying oxidizing gas to said main passage, said inlet passages beingeach much shorter and of smaller cross-sectional area than said mainpassage, and one of said inlet passages being coaxial with said maincylindrical passage.

8. A blowpipe for thermochemically removing ,tively smaller diameterthan said inlet portion in axial alignment with said inlet portionfordischarging a stream of oxidizing gas against a surface of said body;and a spud device fitted into said inlet portion and provided with aplurality of open-ended passages extending length- Wise thereof saidplurality of open-ended passages each having a substantially greaterlength than its greatest transverse dimension and collectivelyconstituting the inlet means for supplying oxidizing gas to saiddelivery portion.

WILGOT J. JAcoBssoN.

gas against a surface of said

